int_arg
static int int_arg(char *s, char *what);
i = int_arg(optarg, "traffic class");
i = int_arg(optarg, "flow label");
i = int_arg(optarg, "type-of-service");
i = int_arg(optarg, "port number");
hoplimit = int_arg(optarg, "ttl");
datalen = int_arg(argv[optind], "data size");
npackets = int_arg(argv[optind],
timeout = int_arg(argv[optind], "timeout");